See this post for how to parse the form fields. Looks like you could check if the data is an array and transform it into a string like this:

$form_data = WPCF7_Submission::get_instance()->get_posted_data();

$table['data'] = array_map(
    function( $field ) {
        if ( is_array( $field ) ) {
            return implode( ', ', $field );
        }

        return strval( $field );
    },
    $form_data
);

I haven’t tested this so I’m not sure if it works and what is the format that TablePress expects `$table[‘data’]` to be.